Parker got plenty of home-run help to pitch his way into Oakland's record book, and the surging A's pulled into a tie atop the American League West with Texas by overpowering the Rangers 11-4 on Wednesday.

''I'm just trying to stay in the moment,'' Parker said.

Parker (11-6) allowed two runs in six innings to extend his unbeaten streak to 18 straight starts, eclipsing Catfish Hunter's Oakland mark set from June 2-Sept. 3, 1973. Parker struck out four and walked none.

The 24-year-old has won his past nine decisions, the most by an A's pitcher since Dan Haren won 10 in a row in 2007. He hasn't lost since May 22 at Texas.

''He goes out there and shuts teams down,'' right fielder Brandon Moss said. ''He puts the ball in play and doesn't walk anybody. When he gets in trouble, he finds a way to dig deep and get himself out of it. That's what aces do.''

Moss, Daric Barton and Coco Crisp each hit two-run homers, and Josh Donaldson added a three-run drive for Oakland. The A's handed Darvish (12-7) a loss in consecutive starts for the first time all season.

Darvish gave up five runs — matching a season high — and tied a career-worst with six walks in five-plus innings. He is 1-5 with a 4.82 ERA against Oakland.

Darvish also made a pointed gesture that appeared to signal catcher A.J. Pierzynski to go back behind the plate during a mound visit by pitching coach Mike Maddux. Pierzynski downplayed the incident.

''He had a command issue. I went out there to calm him down. I wasn't paying attention,'' Pierzynski said.

A's opening day starter Brett Anderson, working his way back from a stress fracture in his right foot, allowed two runs in three innings for his second save. Manager Bob Melvin said he's trying to stretch out Anderson's appearances to give the team the option of inserting him back into the rotation.

A year after the A's completed a three-game sweep over the Rangers to win the division on the final day, the AL West race is again shaping up as a tight one. Oakland has won eight of its past 10 to set up what should be a scintillating September. The teams play three more times in Texas from Sept. 13-16.

''It should be fun,'' Donaldson said.

Darvish struggled with his command from the start, bouncing balls in front of the plate and piling up his pitch count. By the second, he had already matched a season high with four walks and had thrown 42 pitches.

Moss sent his 26th home run of the season over the wall in right in the first, and Crisp drove in the first of his four RBIs in the second with a sacrifice fly.

Leonys Martin hit an RBI double and Craig Gentry singled him home in the third to slice Oakland's lead to 3-2, but the Rangers blew their best chance to rally in the fifth.

Shortstop Jed Lowrie bobbled Jim Adduci's grounder and Martin's sacrifice bunt moved both runners into scoring position. Jurickson Profar broke to the plate on Gentry's comebacker and was tagged out trying to get back to third.

''It wasn't a good day is all,'' Ranger manager Ron Washington said.

Barton's second home run of the season — and first in Oakland since July 10, 2010 — ended Darvish's day. Donaldson's 20th homer came later in the sixth against reliever Robbie Ross, and Crisp's 18th in the eighth put Parker in a powerful position to make history.

The only A's starter with a longer unbeaten streak is Lefty Grove, who won 21 in a row from April 22-Aug. 19, 1931. The Hall of Famer also had 10 relief appearances during the streak, including one loss.

Since dropping his first four decisions this season, Parker has only allowed more than three runs twice.

''He's been nails,'' Donaldson said. ''You need a guy like Parker to come in every day and give us a chance to win, and that's what he's done for the majority of this year.''

NOTES: The Rangers batted out of order in the ninth but nobody reached base so the A's never protested. . . . Rangers SS Elvis Andrus missed his fourth straight game with a sore back. He said he could've played, but with a day off Thursday, Washington wanted to give Andrus extra time to recover. . . . Athletics C Derek Norris, who fractured his left big toe Aug. 21, said he feels ''ready to go'' and expects to be activated from the 15-day disabled list when eligible Thursday.